New Packard Fellow to Build 3-D Molecule Analyzing Spectrometer

A laser-based spectroscopic device for seeing the conformation — the shape and orientation — of any molecule, no matter how complex, is in development. The machine, designed for chemists and researchers who are not laser specialists, should allow them to take snapshots of molecules and acquire in seconds data that formerly took days to collect. The goal is to develop a sophisticated yet routine analytic tool for determining molecular structure.

Junrong Zheng's techniques for seeing the fine details of molecular interactions have earned the Rice University scientist a prestigious Packard Fellowship. He and his team will use the five-year grant that comes with the fellowship to work on the spectrometer project.

Rice University chemist Junrong Zheng will use his Packard Foundation award to build a spectrometer that can determine the conformation of molecules in three dimensions. (Image: Jeff Fitlow/Rice University)

Zheng discovered a method for analyzing the natural vibrations of the bonds that hold molecules together in a way that can determine how far apart those molecules are. Further work led to a 2-D method for finding the angles at which the atoms within a molecule bond.

Now Zheng is preparing to move forward into real-time, 3-D analysis of molecular conformations. Time, effort and money will be required to build a machine capable of looking at molecular details in new ways. A successful effort could mean a significant advance in the study of chemical reactions, protein folding, drug-protein interactions, doped nanomaterials and molecular recognition.

Zheng anticipates that it will take five years to build a full-spectrum, multidimensional spectrometer that can read a wide range of frequencies from the high infrared to the low terahertz.

This year he published a paper in Journal of Physical Chemistry that details his technique for acquiring 3-D data from a specific molecule. The article describes how Zheng and his team analyzed the conformations of a small molecule, 1-cyanovinyl acetate, known to contain a wide range of vibrational energy.

They compared theoretical calculations of the five possible conformations of the molecule to what they saw through physical analysis with a 2-D infrared spectrometer designed by Zheng and his team. The comparison showed theory and experimental results in virtually perfect alignment.

Zheng believed that results for molecules bigger than the fast-moving 1-cyanovinyl acetate would be just as good because their rotations are slower.

Zheng said that the machine, when finished, will probably be the only one of its kind in the world. "Hopefully, we can make it very easy to use, so everybody can go buy one," he said.

The David and Lucille Packard Foundation names 16 award winners every year from among 100 nominees who represent 50 American research universities.

For more information, visit: www.rice.edu